WD 0806−661
WD 0806−661 (L 97-3, GJ 3483), formally named Maru, is a DQ white dwarf with an extremely cold Y-type substellar companion (designated "B"), located in the constellation Volans at 62.7 light-years (19.2 parsecs) from Earth. The companion was discovered in 2011, and is the only known Y-type companion to a star or stellar remnant. At the time of its discovery WD 0806-661 B had the largest actual (2500 AU) and apparent separation (more than 2 arcminutes) of any known planetary-mass object, as well as being the coldest directly imaged substellar object then known.
The right side shows an image taken by ESO's VLT HAWK-I in near-infrared. The white dwarf is marked with an arrow. The left side shows an image taken by the NASA/ESA HST WFC3 also in near-infrared wavelengths. The sub-brown dwarf appears as green pixels (2014) and purple pixels (2015) in an insert. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Volans |
| Right ascension | 08h 06m 53.75366s |
| Declination | −66° 18′ 16.7011″ |
| Characteristics | |
| Spectral type | DQ4.2 + Y1 |
| Apparent magnitude (B) | 13.74 / - |
| Apparent magnitude (V) | 13.71 / - |
| Apparent magnitude (R) | 13.64 / - |
| Apparent magnitude (I) | 13.60 / - |
| Apparent magnitude (J) | 13.704 ± 0.023 / ~25.42 |
| Apparent magnitude (H) | 13.739 ± 0.025 / ~25.29 |
| Apparent magnitude (K) | 13.781 ± 0.043 / - |
| Astrometry | |
| Proper motion (μ) | RA: 335.519(16) mas/yr Dec.: −288.994(17) mas/yr |
| Parallax (π) | 51.9970 ± 0.0141 mas |
| Distance | 62.73 ± 0.02 ly (19.232 ± 0.005 pc) |
| Absolute magnitude (MV) | 12.30 / - |
| Details | |
| Component A | |
| Mass | 0.58 ± 0.03 M☉ |
| Surface gravity (log g) | 8.00 ± 0.05 cgs |
| Temperature | 10205 ± 390 K |
| Age | 1.5–2.7 Gyr |
| Component B | |
| Mass | 7–9 MJup |
| Surface gravity (log g) | 4.2–4.3 cgs |
| Temperature | 325–350 K |
| Metallicity | <0 |
| Position (relative to A) | |
| Component | B |
| Angular distance | 130.2 ± 0.2″ |
| Position angle | 104.2 ± 0.2° |
| Projected separation | 2500 AU |
| Other designations | |
| Database references | |
| SIMBAD | data |
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